Study On Visual Quality Of Myopia And Myopia With Different Correction Mehtods

ObjectiveTo investigate the characteristics of corneal HOAs of the anterior surface,posterior surface,and total cornea in adolescents with mild to moderate myopic eyes,and analyze the correlation between corneal aberration and ocular parameter（corneal curvature and ocular axis）.To evaluate the change of corneal high-order aberration（HOAs）after wearing orthokeratology contact lens and study the influence factors.To investigate the characteristics of aberration of the eyes after small incision lenticule extraction（SMILE）,computate optical modulation transfer function（MTF）and evaluate the relationship between visual acuity（VA）,contrast sensitivity function（CSF）and MTF.MethodsPart 1:A total of 183 patients with myopia（183 eyes）aged 8 to 18-years-old were enrolled in this study.The axial length（AL）of the eyes was measured by IOL-Master and corneal curvatures（K-values）and HOAs(Z₃¹,Z₃^-1,Z₄⁰)were measured by the Pentacam anterior segment diagnostic analyzer.Analyzed the correlation between the higher-order aberrations(Z₃¹,Z₃^-1,Z₄⁰)of the anterior,posterior,and corneal surfaces of the cornea and the eye parameters(length of the eye axis,curvature of the anterior and posterior corneal surface,and diopterPart 2:A series of case observation method was used.46 right myopia eyes of 46children fitted orthokeratology were continuously collected from January to April2018.Corneal aberration(Z₃³,Z₃^-3,Z₃¹,Z₃^-1,Z₄⁰)and corneal eccentricity e values were measured by Pentacam anterior segment analysis before and 1 month after treatment,respectively.Part 3:Thirty-four myopia patients（68 eyes）after SMILE surgery for more than 3 months were enrolled in this study.Under bright vision,measured VA and CSF.The wavefront aberrations of the whole eyes were measured by Wave Scan,and MTF were obtained by using aberration formula conversion.ResultsPart 1:In adolescents with mild to moderate myopia eyes,the anterior,posterior,and total corneal horizontal coma Z₃¹ were（-0.125±0.105,0.001±0.001,and-0.133±0.116）μm,respectively;vertical coma Z₃^-1 were（-0.021±0.164,0.000±0.043,and-0.022±0.168）μm respectively;and SA Z₄⁰ were（0.224±0.091,-0.144±0.029,and 0.189±0.090）μm,respectively.The total corneal Z₃¹ was statistically correlated with the posterior corneal astigmatism（K₂b-K₁b）（P<0.05）.The total corneal Z₃^-1was correlated with the anterior corneal astigmatism（K₂f-K₁f）（P<0.05）.The anterior,posterior,and total corneal Z₄⁰were correlated with anterior and posterior corneal curvature（K₁f,K₂f,K₁b,K₂b）（P<0.05）.The posterior corneal Z₄⁰ b was also significantly correlated with AL.Part 2:After wearing orthokeratology,horizontal coma,vertical coma and spherical aberration（SA）of total cornea and anterior corneal surface were drifted positively,horizontal coma and SA of posterior corneal surface were drifted negatively,the differences were statistically significant（all at P<0.05）.The anterior corneal surface changed from steep to flat after wearing orthokeratology,with statistically significant differences（all at P<0.05）.SA of total cornea was moderately negatively correlated with the corneal e value and initial diopter（r=-0.626,-0.450,both at P<0.05）,the horizontal coma of total cornea was moderately negatively correlated with the temporal e value（r=-0.391,P=0.004）;the SA of the anterior corneal surface was moderately negatively correlated with the corneal e value and initial diopter（r=-0.612,-0.432,both at P<0.05）,and the horizontal coma of the anterior corneal surface was moderately negatively correlated with the temporal e value（r=-0.400,P=0.003）;while the horizontal coma of the posterior corneal surface was negatively correlated with the horizontal coma of the anterior corneal surface（r=-0.380,P=0.009）.Part 3:After small incision lenticule extraction（SMILE）,CSF values in（3,6,12,18）c/deg frequency range were 63.19±3.18,110.25±5.22,57.65±3.76,16.15±1.04;MTF values in（3,6,12,18）c/deg frequency range were 0.80±0.02,0.56±0.03,0.30±0.02,0.19±0.02.In（6,12,18）c/deg frequency range,visual acuity was significantly correlated with CSF（r=0.548,0.337,0.324,P<0.001,=0.005,0.007）.In 18c/deg frequency range,CSF was significantly correlated with MTF（r=0.241,P=0.048）.ConclusionPart 1:In adolescents with mild to moderate myopic eyes,corneal SA is the most important HOAs of the cornea and as the cornea tends to be flat,the corneal SA tends to become less positive.The posterior corneal surface shape shows a compensatory role in the balance of corneal aberrations and the posterior corneal SA tended to become less negative as the axial length increased.The corneal coma also compensated posterior corneal surface astigmatism,which may contribute to visual quality.Part 2:The spherical aberration and coma of total cornea and anterior corneal surface drift positively after wearing orthokeratology contact lens,the spherical aberration and horizontal coma of the posterior corneal surface drift negatively.The refraction and deformation of the anterior surface of the cornea are important factors for the variation of corneal high-order aberration.Part 3:The change of optical quality（MTF）after SMILE was different from that of visual quality（visual acuity and contrast sensitivity）.Although the aberration of refractive system changed,the SMILE surgery had no effect on CSF of the whole eye,which indicated that neuro-brain had a compensatory effect on visual quality.Computational MTF has certain theoretical and clinical value in evaluating the optical quality after refractive surgery.